Nannotax3 - ntax_cenozoic - Prinsius dimorphosus

Citation: Prinsius dimorphosus (Perch-Nielsen, 1969) Perch-Nielsen 1977

Basionym: Biscutum dimorphosum Perch-Nielsen, 1969

Synonyms:

Praeprinsius dimorphosus (Perch-Nielsen, 1969) Varol & Jakubowski 1989

Taxonomic discussion: The name dimorphosus referred to observation of coccospheres with a mix of coccoliths with either a simple tube-cycle or a double tube-cycle. Subsequently Okada & Thierstein (1979) separated their species tenuiculus from dimorphosus based on coccolith outline - (sub)circular vs elliptical. This differentiation was compatible with the type specimens of Perch-Nielsen (1969) and has been widely followed.

Distinguishing features:
Parent taxon (Prinsius): Small to medium size (3-6 µm), elliptical, central areas narrow, closed or with slit-like opening
This taxon: Very small, elliptical to subcircular placoliths with narrow to closed central area.

Original description: [Translated description - from Google translate with edits - JRY 2019]
Diagnosis: Elliptical coccoliths with a distal marginal wall of juxtaposed to slightly overlapping elements and a central field filled with one or two layers of elements. Basal side unknown.
The coccosphaere consists of about 8-14 mutually overlapping coccoliths of different or the same structure.

Description: The distal shield is made up of approximately 12-15 wide, marginal elements that are adjacent to each other or overlap slightly. The central field of the coccolith is filled in one form by a number of large crystals of different size and shape, while in other coccoliths a ring of other elements is interposed between these central elements and the marginal elements. These are arranged in such a way that only one corner in each case protrudes under the central elements, similar to a serrated collar. The coccosphere consists of 8-14 coccoliths of one or the other form, or both forms, and has the shape of a flattened sphere. The coccoliths overlap each other quite strongly.

Basal sides of the coccoliths could not be determined with certainty. The simpler form is not found as a single coccolith, and although the three-step form is not uncommon as single coccoliths, it appears that it is mostly sedimented on the formvar film in such a way that only the distal side is visible

Geological Range:
Last occurrence (top): within NP4 zone (61.51-63.25Ma, top in Selandian stage). Data source: Perch-Nielsen 1985b
First occurrence (base): in upper part of NP2 zone (60% up, 65.1Ma, in Danian stage). Data source: Varol, 1989, fig. 12.4

References:

Bown, P. R., Kim, H. & Gibbs, S. J. (2023). Danian calcareous nannofossil evolution and taxonomy with focus on sites from the North Atlantic Ocean (IODP Expedition 342, Sites U1403 and U1407). Journal of Nannoplankton Research. 41(2): 110-157. gs O

Burnett, J. A. (1998). Upper Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 132-199. gs O

Mai, H. (2001). New coccolithophorid taxa fom the Guelhemmerberg airshaft. Lower Paleocene, The Netherlands. Micropaleontology. 47: 144-154. gs

Mai, H., von Salis, K., Willems, H. & Romein, A. J. T. (1997). Fossil coccospheres from the K/T boundary section from Geulhemmerberg, The Netherlands. Micropaleontology. 43: 281-303. gs

Mai, H., Hillebrandt-Habel, T., von Salis Perch-Nielsen, K. & Willems, H. (1998). Paleocene coccospheres from DSDP Leg 39, Site 356, Sao Paulo Plateau, S. Atlantic Ocean. Journal of Nannoplankton Research. 20(1): 21-29. gs

Okada, H. & Thierstein, H. R. (1979). Calcareous nannoplankton - Leg 43, Deep Sea Drilling Project. Initial Reports of the Deep Sea Drilling Project. 43: 507-573. gs O

Perch-Nielsen, K. (1969). Elektronenmikroskopische Untersuchungen der Coccolithophoriden der Dan-Scholle von Katharinenjof (Fehmarn). Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen. 132: 317-332. gs

Perch-Nielsen, K. (1969). Die Coccolithen einiger danischer Maastrichtien- und Danienlokalitaten. Meddelelser fra Dansk Geologisk Forening. 19: 51-68. gs

Perch-Nielsen, K. (1972). Remarks on Late Cretaceous to Pleistocene coccoliths from the North Atlantic. Initial Reports of the Deep Sea Drilling Project. 12: 1003-1069. gs

Perch-Nielsen, K. (1977). Albian to Pleistocene calcareous nannofossils from the Western South Atlantic, DSDP Leg 39. Initial Reports of the Deep Sea Drilling Project. 39: 699-823. gs O

Perch-Nielsen, K. (1979). Calcareous nannofossil zonation at the Cretaceous/Tertiary boundary in Denmark. In, Birkelund, T. & Bromley, R. G. (eds) Proceedings Cretaceous-Tertiary Boundary Events Symposium, Copenhagen, 1. Copenhagen 115-135. gs O

Perch-Nielsen, K. (1981). New Maastrichtian and Paleocene calcareous nannofossils from Africa, Denmark, and USA and the Atlantic, and some Paleocene lineages. Eclogae Geologicae Helvetiae. 74(3): 831-863. gs O

Perch-Nielsen, K. (1985). Cenozoic calcareous nannofossils. In, Bolli, H. M., Saunders, J. B. & Perch-Nielsen, K. (eds) Plankton Stratigraphy. Cambridge University Press, Cambridge (1): 427-555. gs

Pospichal, J. J. & Bralower, T. J. (1992). Calcareous Nannofossils Across the Cretaceous/Tertiary Boundary, Site 761, Northwest Australian Margin. Proceedings of the Ocean Drilling Program, Scientific Results. 122: 735-752. gs

Pospichal, J. J. & Wise, S. W. (1990). Calcareous nannofossils across the K/T boundary, ODP hole 690C, Maud Rise, Weddell Sea. Proceedings of the Ocean Drilling Program, Scientific Results. 113: 515-532. gs

Pospichal, J. J. & Wise, S. W. (1990). Paleocene to Middle Eocene calcareous nannofossils of ODP sites 689 and 690, Maud Rise, Weddell Sea. Proceedings of the Ocean Drilling Program, Scientific Results. 113: 613-638. gs

Self-Trail, J. M., Parker, M., Govoni, D. L., Bybell, L. M., Gardner, K. F. & Gohn, G. S. (2023). Designation of a composite-stratotype section for the lower Paleocene (Danian) Brightseat Formation in Prince George’s County, Maryland, USA. Stratigraphy. 20(4): 237-258. gs

Varol, O. & Jakubowski, M. (1989). Some new nannofossil taxa. INA Newsletter. 11(1): 24-29. gs

Varol, O. (1989c). Palaeocene calcareous nannofossil biostratigraphy. In, Crux, J. A. & van Heck, S. E. (eds) Nannofossils and their applications: Proceedings of the 2nd INA Conference, London 1987. British Micropalaeontological Society Publication Series . 265-310. gs

Varol, O. (1998). Palaeogene. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 200-224. gs

Prinsius dimorphosus

References:

Add Comment

Comments